Wrought zinc alloy

ABSTRACT

Wrought zinc alloy comprising 0.01 to 0.30% titanium, 0.01 to 2.00% manganese, 0.01 to 2.00% aluminum, balance zinc (99.9 to 99.99%). The alloys have a high creep resistance, a high ductility and a high tensile strength.

United States Patent Pelzel et al.

[ Nov. 13, 1973 WROUGHT ZINC ALLOY Inventors: Erich Pelzel, Puchheim, near Munich; Reiner Pelzel, Munich-Lochhausen, both of Germany Metallgesellschaft AG, Frankfurt am Main, Germany Filed: Feb. 23, 1971 Appl. No.: 118,170

Assignee:

Foreign Application Priority Data Feb. 24, 1970 Germany P 20 08 525.0

References Cited UNITED STATES PATENTS 10/1947 Boyle et al. 75/178 R 10/l96l Giuliani et al. 75/178 R 9/1970 Foerster 75/178 C FOREIGN PATENTS OR APPLICATIONS 1,319,535 1/1963 France 75/178 R Primary Examiner-I... Dewayne Rutledge Assistant Examiner-E. L. Weise Attorney--Michael S. Striker [5 7] ABSTRACT Wrought zinc alloy comprising 0.01 to 0.30% titanium, 0.01 to 2.00% manganese, 0.01 to 2.00% aluminum, balance zinc (99.9 to 99.99%).

The alloys have a high creep resistance, a high ductility and a high tensile strength.

3 Claims, No Drawings WROUGHT ZINC ALLOY BACKGROUND OF THE INVENTION The invention relates to a zinc-titanium wrought alloy and a method of working it.

A wrought zinc alloy for sheets, strips, tubes, rods and wire, in addition to the requirement of adequate strength properties must also be suited for perfect cold working by folding, bending, pressure application and drawing. These properties are obtained in many of the wrought zinc alloys employed in industry.

It is for instance known (METALL 23 1969 issue 8, pages 782-785) that titanium-containing wrought zinc alloys with 0.05 to 0.5% titanium and 0.05 to 1.50% copper have a good creep resistance which reaches its maximum by hot working at temperatures of 150 to 300C or cold working with subsequent hot working at temperatures between 150 and 300C. The tensile strength in these cases increases with increasing copper contents from about 11 kp/mm to 28 kp/mm while at the same time the creep resistance increases from 6 kp/mm to 9 kp/mm and the residual elongation is limited to 1 percent per year. The increase of the creep resistance is principally obtained by a superfine grain due to the titanium contents. However, the increase in strength of the zinc alloy is undesirably associated with a strong increase of the elasticity. The resultant rebound therefore is an obstacle for a permanent set or deformation of the sheets or strips which are for instance shaped by machines to channel-formed members or tubes.

Furthermore, with an increase of the copper contents the cold brittleness of these zinc alloys increases fairly substantially. The formed sheets and strips therefore have a small ductility as can be determined by means of the folding test. For instance sheets and strips show' indications of fracture at a direct folding by 180 at room temperature and below. A break-free folding by 180 is possible only if the wrought alloy is hot worked or cold worked with a subsequent heat treatment.

An improvement of the shapability of ductility at comparatively low temperatures is obtained if the copper content is limited to about 0.15 percent. In this case however there results a decrease of the tensile strength to 15 to 18 kp/mm.

It is accordingly an object of the present invention to avoid these shortcomings and more specifically to provide for a zinc wrought alloy which has an optimum combination of creep resistance, plasticity or ductility and tensile strength.

SUMMARY OF THE INVENTION The invention resides in a titanium-containing wrought zinc alloy of the following composition:

0.01 to 0.30% titanium 0.01 to 2.00% manganese balance zinc 99.9 to 99.99.

Preferably the manganese content is between 0.04 and 1.20 percent.

The invention also involves a process for improving the properties of the alloy by subjecting it to hot rolling at 120 to 350C to the desired final dimensions or cold rolling to the final dimensions at temperatures between 20 and 120C followed by aging for at least one hour at 120 to 350C.

DESCRIPTION OF THE INVENTION AND OF PREFERRED EMBODIMENTS F cent.

To obtain the maximum properties in the alloy of the invention there should not be present, as impurities, more than 0.15 percent total content of copper and in no case more than up to 25 percent of the contents of manganese. Likewise the iron should not be in excess of 10 percent of the manganese contents and the maximum should be 0.03 percent.

Under normal circumstances adequate creep resistance is obtained for practical purposes. However, if it is desired to attain particularly high values it is advisable to subject the wrought alloy to hot rolling to final dimensions at temperatures between and 350C or to subject it to cold rolling to final dimensions at temperatures between 20 and 120C in which latter case the alloy should be aged for at least 1 hour at temperatures between 120 and 350C. The heat treatments suggested do not affect in any manner the other properties of the wrought alloy.

The following examples will further illustrate the invention. The alloys described in these examples were obtained by mixing in molten condition and were then cast at 450C to ingots of a thickness of 80 mm each. After solidification the ingots were cooled rolled in order to form sheets and strips of a thickness of 1 mm. The cold rolling was effected in several passes. Subsequent the elongation, tensile strength, creep resistance and foldability were determined to obtain a picture of the properties of the alloy.

EXAMPLE 1 Zinc wrought alloy of the composition:

manganese 0.80%

titanium 0.15%

balance high-grade zinc 99.99%.

The properties of the alloy were as follows:

Elongation at break 40 percent Tensile strength 25 kp/mm Creep resistance 1O kp/mm at 1% elongation per year Foldability 180 without break EXAMPLE 2 Wrought zinc alloy of the composition:

manganese 0.40%

titanium 0.10%

aluminum 0.05%

balance high-grade zinc 99.99%.

The properties of the alloy were as follows:

Elongation at break 60 percent Tensile strength 20 kp/mm Creep resistance 8 kp/mm at 1 percent elongation per year Foldability 180 without break EXAMPLE 3 Wrought zinc alloy of the composition:

manganese 0.30%

titanium 0.03%

aluminum 0.70%

balance high-grade zinc 99.99%.

The properties of the alloy were as follows:

Elongation at break 100% Tensile strength 20 lcplmm Creep resistance 4 kp/mrn at 1 percent elongation per year Foldability 180 without break.

The accomplishments of the alloys of the invention are particularly in the features of a high ductility and high tear resistance along with a high creep resistance.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended 1. A wrought zinc alloy containing between 0.01 and 0.30% titanium, or chromium replacing a portion of the titanium in an amount up to 0.1 percent but not more than 50 percent of the titanium content, between 0.01 and 2.00% manganese, between 0.005 and 0.80% aluminum, copper in an amount up to 0.15 percent but not more than 25 percent of the manganese content, and iron in an amount up to 0.03 percent but not more than 10 percent of the manganese content, the balance of the alloy being zinc.

2. A wrought zinc alloy containing 0.40% manganese, 0.10% titanium, 0.05% aluminum, and the balance of the alloy being zinc.

3. A wrought zinc alloy containing 0.30% manganese, 0.03% titanium, 0.70% aluminum, and the balance of the alloy being zinc. 

2. A wrought zinc alloy containing 0.40% manganese, 0.10% titanium, 0.05% aluminum, and the balance of the alloy being zinc.
 3. A wrought zinc alloy containing 0.30% manganese, 0.03% titanium, 0.70% aluminum, and the balance of the alloy being zinc. 